Camshaft Position Sensor: Description and Operation

Sync Signal Generator Operation:

LOCATION

The camshaft position sensor is located in the distributor housing under the ignition rotor and pulse ring.


PURPOSE

The signal from the camshaft position sensor combined with the input signal from the Crankshaft Position Sensor, are what the engine controller uses to differentiate between fuel and spark events. Input is also used to properly synchronize fuel injection.


OPERATION

The camshaft position sensor consists of a hall effect switch and a pulse ring that is mounted to the distributor shaft. As the leading edge of the pulse ring passes the hall effect switch, the change in the magnetic field induces a voltage rise of 5 volts. This 5 volt signal indicates to the engine controller that the next piston to come to TDC is number 4. When the trailing edge of the pulse ring leaves the switch, the collapse of the magnetic field causes the voltage to drop to 0 volts. A signal of 0 volts indicates to the engine controller that piston number 1 is the next piston to reach TDC.

The camshaft position sensor is used to reference number 1 and 4 cylinders, it sends voltage to the engine controller and works in conjunction with the Crankshaft Position Sensor so that the engine controller can establish and maintain the correct injector synchronization.

If engine controller does not sense input from sensor, it will deactivate ASD and fuel pump relay, interrupting voltage to fuel pump, fuel injectors, and ignition coil, causing a no start condition.